Apparatus for treating objects with a treatment fluid

ABSTRACT

There is described an apparatus for treating objects with a treatment fluid, more especially an etching or developing machine for the production of printed-circuit boards, wherein the nozzle stock comprising a plurality of nozzles is designed so as to be plate-like. The edges of the plate-like nozzle stock are tightly connected to the housing walls so that the treatment chamber, to which the treatment fluid is applied, is bounded by the nozzle stock in one direction. The nozzles can be fitted and possibly also rotated through the nozzle stock from the side that is directed away from the treatment chamber, so that an effortless exchanging or aligning of the nozzles is possible from outside the treatment chamber (FIG. 1).

The invention relates to an apparatus for treating objects with atreatment fluid, more especially an etching or developing machine forthe production of printed-circuit boards, comprising a nozzle stockwhich is provided inside a housing and which comprises a plurality ofnozzles, which are directed towards a treatment chamber, and a channelsystem for feeding the treatment fluid to the nozzles.

On known etching and developing machines for the production ofprinted-circuit boards, the nozzle stock is formed by the feedingchannels themselves, which constitute an open supporting frame for thenozzles and are situated entirely inside the treatment chamber. Theexchanging and setting of the nozzles is extremely troublesome in thisconstruction since the treatment chamber is filled with etching-mediumresidues and etching-medium vapours, which are corrosive andevil-smelling.

It is the object of the present invention to design an apparatus of thekind mentioned at the beginning in such a way that the fitting,exchanging and possibly the angular setting of the nozzles is possibleeasily and without any impairment due to residues and vapours of thetreatment fluid.

According to the invention, this problem is solved in that

(a) the nozzle stock is designed so as to be plate-like;

(b) the edges of the nozzle stock are tightly connected to the walls ofthe housing of the apparatus;

(c) the nozzles are insertable from the side of the nozzle stock that isdirected away from the treatment chamber and can be passed through achannel in the nozzle stock and project with a neck from the side of thenozzle stock that is directed towards the treatment chamber.

In the plate-like design of the nozzle stock according to the invention,the stock tightly bounds the treatment chamber towards one side. Thenozzles can be fitted or exchanged from the "rear", namely the side thatis directed away from the treatment chamber, of the nozzle stock. Adismantling of the nozzles is frequently necessary, particularly if itturns out that one of the nozzles is clogged and a search for therespective unsatisfactorily working nozzle has to be carried out.

Expediently, the nozzle is also rotatable inside the nozzle stock fromthe side that is directed away from the treatment chamber. The rotationof the nozzles, which is particularly important for the setting offan-shaped or flat spray nozzles, may be effected during the operationof the apparatus.

A particularly appropriate construction of the apparatus is to theeffect that the nozzle stock comprises for each nozzle:

(d) a first through bore which connects the side that is directed awayfrom the treatment chamber to a channel and which has a first diameter;

(e) a second through bore which connects the channel to the side that isdirected towards the treatment chamber and which has a second diameterthat is smaller than the first diameter;

and that each nozzle is designed as a substantially cylindrical insertand comprises:

(f) a first zone having a diameter that is larger than the diameter ofthe first through bore;

(g) a second zone having a diameter that is somewhat smaller than thediameter of the first through bore but is larger than the diameter ofthe second through bore;

(h) a nozzle neck whose diameter is smaller than the diameter of thesecond through bore;

(i) an internal cavity;

(k) at least one channel extending radially from the cavity;

(l) an axial channel connecting the cavity to the face of the nozzleneck;

the ring shoulder connecting the first zone to the second zone tightlyabutting a surface which is located on the side of the channel that isdirected away from the treatment chamber and the ring shoulderconnecting the second zone to the nozzle neck tightly abutting a surfacewhich is located on the side of the channel that is directed towards thetreatment chamber.

It is of advantage if the face of the nozzle that is directed away fromthe treatment chamber is provided with a mark indicating the rotationalposition of the nozzle within the nozzle stock. In this way, it ispossible at any time to find out at a glance what angular positions thevarious installed nozzles have. With each mark there may be associatedon the nozzle stock a scale so that once an optimum setting of thenozzles has been found it can be recorded in writing and can bereproducibly re-established according thereto.

The mark may simultaneously constitute the means to which the force forrotating the nozzle is applied. This means may be formed, for example,by a screw driver slot.

Expediently, the nozzle is fastened to the nozzle stock by means of acap nut which is screwed on a collar provided with an external threadand located at the side of the nozzle stock that is directed away fromthe treatment chamber.

The nozzle stock may be reduced in thickness in the zones outside thechannels so that the channel system is embossed on one side and/or theother side of the nozzle stock. In this way, material is saved; thenozzle stock as a whole becomes lighter.

Hereinafter, an exemplified embodiment of the invention will beexplained in more detail with reference to the drawings, in which

FIG. 1 diagrammatically shows a section through an etching machine(nozzle stock not sectioned);

FIG. 2 shows a top view of the nozzle stock shown in FIG. 1;

FIG. 3 shows a partial section through the nozzle stock of FIGS. 1 and 2on an enlarged scale.

In FIG. 1, there is diagrammatically shown a section through an etchingmachine for the production of printed-circuit boards. The componentswhich are not necessary to understand the invention have not been shownfor the sake of clarity.

The etching machine comprises a housing which stands on feet 1 and isprovided with side walls 2a, a bottom wall 2b and possibly a top wall2c. The latter may be dispensed with, but in any event it should beeasily removable (e.g. swingable or slidable).

The material to be etched is transported from a material inlet 3 to amaterial outlet 4 by a roller conveyor system 5 and is sprayed with anetching medium during this process. In order to prevent any treatmentfluid from being transmitted from the machine arranged upstream of theetching machine into the etching machine and from the etching machineinto the machine arranged downstream thereof, there are provided at thematerial inlet 3 and the material outlet 4 squeeze rolls 6 and 7respectively.

The spraying of the material to be etched is effected by means of anozzle stock 8 which is designed in a plate-like manner and in whichthere are provided a plurality of individual nozzles 9 in a specificpattern (see also FIG. 2). The etching medium sprayed from the nozzles 9is collected in a sump 10, from which it is conveyed by a pump not shownvia a line also not shown to a connection 11 on the nozzle stock 8. Fromthere, the etching medium flows via a channel system 12 formed withinthe nozzle stock 1 to the individual nozzles 9 (see FIGS. 2 and 5).

The plate-like nozzle stock 8 has been tightly placed on brackets 13(FIG. 1) fastened to the side walls 2a, for which purpose seals may beinterposed. In this way, the etching chamber is bounded towards the topwithin the etching machine; the space above the nozzle stock 8 staysfree from etching medium and etching-medium vapour.

The nozzles 9 are fitted from the side of the nozzle stock 8 that isdirected away from the etching chamber, as is apparent from FIG. 3 inparticular. To this end, the nozzle stock 8 has at the points where anozzle 9 is to be provided an upper through bore 14, which connects theupper nozzle stock side to the respective channel 12, as well as a lowerthrough bore 15, which connects the channel 12 to the underside of thenozzle stock 8. The diameter of the upper through bore 14 is larger thanthat of the lower through bore 15.

The nozzle 9 is shaped as a substantially cylindrical insert with (atleast) two steps. Its uppermost zone 9a, which is largest in diameter,is connected via a first downwardly pointing ring shoulder 16 to acentral zone 9b, whose diameter is somewhat smaller than the diameter ofthe upper through bore 14 of the nozzle stock 8. The central nozzle zone9b is connected via a second downwardly pointing ring shoulder 17 to anozzle neck 9c, whose diameter is smaller than the diameter of thesecond through bore 15.

The nozzle 9 has an internal cavity 18 which is in communication withthe nozzle opening 20 at the lower front end of the nozzle neck 9c viaan axially extending channel 19 and with the channel 12 via severalradial channels 21.

The nozzle 9 is introduced from the top through the through bores 14,15, and consequently also through the channel 12, so that its lower ringshoulder 17 rests on the lower internal wall of the channel 12 and itsupper ring shoulder 16 rests on the upper face of a fastening collar 22provided with an external thread and integrally formed with the nozzlestock 1. The entire nozzle is fixed in this position by a cap nut 23which has been screwed on the fastening collar 22.

O-rings have been inserted into grooves in the ring shoulders 16 and 17respectively and ensure sealing of the respective counter-surfaces. Atleast the lower O-ring may be dispensed with since the leaking ofetching medium from the channel 12 can be tolerated here to a slightextent and sealing that is adequate in this respect is attainable bysuitable machining of the juxtaposed plastics material surfaces.

As can be seen, the nozzle 9 is rotatable in its fitted position, forwhich purpose a screw-driver slot 24 has been recessed into its upperface. The screw-driver slot 24 simultaneously serves as a mark whichreveals the relative rotational position of the nozzle within the nozzlestock 8 from the top (see also FIG. 2).

The above-described exemplified embodiment relates to a continuouslyoperating etching machine with a horizontal stationary nozzle stock 8.Of course, the described design of the nozzle stock as a plate can alsobe used for other etching machines. In particular, the installedposition of the nozzle stock 8 (horizontal, vertical) and the number ofnozzle stocks are of no importance. If the nozzle stock 8 as a whole isto carry out a reversing and/or oscillating movement, the tightconnection of the nozzle stock 8 to the side walls 2a has to be effectedvia a flexible bellows, a flexible/elastic cloth or the like.

Of course, the thickness of the plate-like nozzle stock 8 may be reducedin the zone outside the channels 12 so that the channel system willstand out in an embossed manner towards the top and/or the bottom inFIG. 1.

I claim:
 1. An apparatus for treating objects introduced into a treatingchamber with a treatment fluid, more especially an etching or developingmachine for the production of printed-circuit boards, comprising anozzle stock which is provided inside a housing and which includes aplurality of nozzles that are directed towards the treatment chamber,and a channel system for feeding the treatment fluid to said nozzles,characterized in that(a) the nozzle stock (8) is in the form of aplate-like member, (b) the edges of the plate-like member of the nozzlestock (8) are tightly connected to the walls (2a) of the housing of theapparatus so as to define one wall of the treatment chamber. (c) thenozzles (9) are insertable from the side of the nozzle stock (8) that isdirected away from the treatment chamber and can be passed through achannel (12) in the nozzle stock (8) and project with a neck (9c) fromthe side of the nozzle stock (8) that is directed towards the treatmentchamber.
 2. An apparatus as claimed in claim 1, characterised in thatthe nozzles (9) are rotatable inside the nozzle stock (8) from the sidethat is directed away from the treatment chamber.
 3. An apparatus asclaimed in claim 1, characterized in that the nozzle stock (8) comprisesfor each nozzle (9):(d) a first through bore (14) connecting the sidethat is directed away from the treatment chamber to a channel (12) andhaving a first diameter; (e) a second through bore (15) connecting thechannel (12) to the side that is directed towards the treatment chamberand having a second diameter, which is smaller than the firstdiameter;and in that each nozzle (9) is designed as a substantiallycylindrical insert and comprises: (f) a first zone (9a) having adiameter that is larger than the diameter of the first through bore(14); (g) a second zone (9b) having a diameter that is somewhat smallerthan the diameter of the first through bore (14) but is larger than thediameter of the second through bore (15); (h) a nozzle neck (9c), whosediameter is smaller than the diameter of the second through bore (15);(i) an internal cavity (18); (k) at least one channel (21) extendingradially from the cavity (18); (l) an axial channel (19) connecting thecavity (18) to the face of the nozzle neck (9c);the ring shoulder (16)connecting the first zone (9a) to the second zone (9b) tightly abuttinga surface which is located on the side of the channel (12) that isdirected away from the treatment chamber and the ring shoulder (17)connecting the second zone (9b) to the nozzle neck (9c) tightly abuttinga surface which is located on the side of the channel that is directedtowards the treatment chamber.
 4. An apparatus as claimed in claim 2,characterised in that the front of the nozzle (9) that is directed awayfrom the treatment chamber is provided with a mark (24) which indicatesthe rotational position of the nozzle (9) within the nozzle stock (8).5. An apparatus as claimed in claim 4, characterised in that the mark(24) simultaneously constitutes the means to which the force forrotating the nozzle (9) is applied.
 6. An apparatus as claimed in claim1, characterised in that the nozzles (9) are each fastened to the nozzlestock (8) by means of a cap nut (23) which has been screwed on a collar(22), which is provided with an external thread and is located at theside of the nozzle stock (8) that is directed away from the treatmentchamber.
 7. An apparatus as claimed in claim 1, characterised in thatthe nozzle stock (8) is reduced in thickness in the zone outside thechannels (12) so that the channel system (12) is embossed on one sideand/or the other side of the nozzle stock (8).
 8. An apparatus fortreating objects introduced into a treating chamber with a treatmentfluid, more especially an etching or developing apparatus for theproduction of printed circuit boards, comprising in combination(a) ahousing, (b) a planar member extending across the upper portion of saidhousing so as to define therebelow a treating chamber, (c) a network offluid passageways extending horizontally across said planar member, (d)a fluid inlet in said housing for introducing fluid into said network offluid passageways, and an outlet for fluid from said treating chamber,and (e) a plurality of nozzles positioned in a pattern in said planarmember, said nozzles(1) being located at spaced apart points thatintersect said network of fluid passageways, (2) being directeddownwardly below said planar member and toward said treating chamber,and(3) being insertable into said planar member from above and having aneck portion that is adapted to discharge fluid received from said fluidpassageways into said treating chamber.
 9. An apparatus as claimed inclaim 8 wherein said nozzles (9) are rotatable inside the planar member(8) from the side that is directed away from the treatment chamber. 10.An apparatus as claimed in claim 8 wherein the planar member (8)comprises for each nozzle (9):(a) a first through bore (14) connectingthe side that is directed away from the treatment chamber to a channel(12) and having a first diameter, (b) a second through bore (15)connecting the channel (12) to the side that is directed towards thetreating chamber and having a second diameter, which is smaller than thefirst diameter,and in that each nozzle (9) is designed as asubstantially cylindrical insert and comprises: (c) a first zone (9a)having a diameter that is larger than the diameter of the first throughbore (14); (d) a second zone (9b) having a diameter that is somewhatsmaller than the diameter of the first through bore (14) but is largerthan the diameter of the second through bore (15); (e) a nozzle neck(9c) whose diameter is smaller than the diameter of the second throughbore (15); (f) an internal cavity (18), (g) at least one channel (21)extending radially from the cavity (18), (h) an axial channel (19)connecting the cavity (18) to the face of the nozzle neck (9c),the ringshoulder (16) connecting the first zone (9a) to the second zone (9b)tightly abutting a surface which is located on the side of the channel(12) that is directed away from the treatment chamber and the ringshoulder (17) connecting the second zone (9b) to the nozzle neck (9c)tightly abutting a surface which is located on the side of the channelthat is directed towards the treatment chamber.
 11. An apparatus asclaimed in claim 8 wherein the front of the nozzle (9) that is directedaway from the treatment chamber is provided with a mark (24) whichindicates the rotational position of the nozzle (9) within the planarmember (8).
 12. An apparatus as claimed in claim 11 wherein the mark(24) simultaneously constitutes the means to which the force forrotating the nozzle (9) is applied.
 13. An apparatus as set forth inclaim 8 wherein the nozzles (9) are each fastened to the planar member(8) by means of a cap nut (23) which has been screwed on a collar (22),which is provided with an external thread and is located at the side ofthe planar member (8) that is directed away from the treatment chamber.14. An apparatus as set forth in claim 8 wherein the planar member (8)is reduced in thickness in the zone outside the channels (12) so thatthe channel system (12) is embossed on one side and/or the other side ofthe planar member (8).